In a large print equipment, which is for example a large format printer or the like utilizing a roller to transport papers, one of the most popular issues is that a paper may be tilted or shrunk inwardly during transportation that makes the paper stuck or broken. The reason causing those issues may be a bad installation, a bad adjustment or the low precision. Especially, when the rollers of the paper-feeding mechanism, which are respectively located at the left side and the right side, have different feeding rates, the velocities of the left side of the paper and the right side of the paper will be different. If the feeding directions of the left side and the right side of the paper are both tilted inwardly and toward the center of the paper, the paper is easily broken or wrinkled.
Please refer to FIG. 1. FIG. 1 schematically illustrates the paper-feeding mechanism of a conventional print equipment and the paper. As shown in FIG. 1, a paper-feeding mechanism is assembled by two active rollers 11 on the top and two corresponded passive rollers 12 on the bottom. The rotation direction R of the active rollers 11 is clockwise direction. A paper 13 is entered from the right side and rolled in so as to be driven to the left side. At this time, if the geometric shapes, sizes and/or angles of the active rollers 11 and the passive rollers 12 are not ideal enough, the feeding rates or feeding angles of the two sides will be not synchronous. It further causes the paper being tilted or shrunk inwardly and makes the paper stuck or broken.
Please refer to FIG. 2 and FIG. 3. FIG. 2 schematically illustrates the conventional paper-feeding mechanism with a crankshaft installed with active rollers having different diameters and the paper transproted by the active rollers. FIG. 3 schematically illustrates an active roller of the conventional paper-feeding mechanism has different diameters respectively at the left side and the right side and the paper transported by the active roller. The exaggerated diagrams of poor precision or bad assembly are shown in FIG. 2 and FIG. 3. When a plurality of active rollers 11 having different diameters are installed on a shaft 14, the feeding rates of the paper 13 are different (the length of the arrow represents the feeding rate). The bending of the shaft 14 itself also causes the paper to be skewed in the feeding direction. When the same active roller 11 has different diameters respectively at the left side and the right side, the different feeding rates of the left side and the right side of the paper 13 causes the paper to be skewed continuously. In brief, the conventional paper-feeding mechanism usually makes the paper to be tilted and shrunk inwardly and further causes the paper to be broken or wrinkled. Not only being inconvenient, but also wasting the print materials.
Therefore, there is a need of providing an improved roller-type lateral force generation device distinct from the prior art in order to solve the above drawbacks.